The present invention relates to implantable leads generally and more particularly to implantable cardioversion and defibrillation leads.
Commercially marketed implantable cardioversion and defibrillation leads often have employed cardioversion/defibrillation electrodes taking the form of elongated conductive coils mechanically coupled to elongated coiled conductors located within the lead body. More recently, there has been a renewed interest in stranded or cabled conductors in the context of implantable electrical leads. For example, such conductors are described in U.S. Pat. No. 5,584,873 issued to Shoberg et al. and in U.S. Pat. No. 5,246,014 issued to Williams et al. In the context of implantable cardioversion and defibrillation electrodes it has been proposed to employ extensions of the conductor within the lead body which are exposed to the exterior of the lead body as cardioversion or defibrillation electrodes. For example, U.S. Pat. No. 5,005,587 issued to Scott discloses the conductor in the form of a hollow metal braid, exposed to the exterior of the lead body over a length of the lead and useful as a defibrillation electrode. U.S. Pat. No. 5,143,089 issued to Alt and U.S. Pat. No. 5,336,254 issued to Brennan et al. disclose braided carbon fiber conductors which extend within the body of a defibrillation lead which also serve as cardioversion/defibrillation electrodes where they are exposed to the exterior of the lead body.
In currently manufactured cardioversion/defibrillation leads, it is not uncommon for the exposed electrode to be coupled to a separately formed coiled or stranded conductor at both ends of the exposed electrode coil. Such electrodes are illustrated in U.S. Pat. No. 5,676,694 issued to Boser et al.